Determination of Chloramphenicol Residues in Honey by Monolithic Column Liquid Chromatography–mass Spectrometry after Use of Q

An HPLC method with a monolithic column and detection by mass spectrometry has been established for determination of chloramphenicol in honey samples previously cleaned by use of a modification of the QuEChERS procedure. Honey samples were dissolved in water containing sodium chloride and extracted with acetonitrile. Further sample clean-up was performed by simple reversed-solid-phase dispersion with primary–secondary amine (PSA) adsorbent. Chloramphenicol (CAP) residues at ppb concentrations were detected by liquid chromatography–mass spectrometry (LC–MS), with electrospray ionization, in negative-ion mode. The mobile phase was methanol–0.2% aqueous ammonium acetate solution, 45:55 (v/v). Under these conditions CAP is eluted after ~4 min and 8 min from a Merck RP18e monolithic column and a conventional C18 column, respectively. Recovery at three fortification levels (0.2, 20, and 200 μg kg) was in the range 78–93% with RSD from 3.7 to 3.9%. The coefficient of determination, R, was 0.9995 over a 0.1–100 μg L linear range. Use of this method for determination of CAP in honey resulted in an LCL of 0.20 μg kg. The method was validated on the basis of EU decision 2002/657. CCα and CCβ for the honey matrix were 0.002 and 0.006 μg kg, so the method was fit for the purpose of monitoring commercial products or checking MRL compliance.